The intention in providing a force limiter is to limit the force maximally active in the belt webbing when the blocking system is activated to a value which is uncritical for the restrained vehicle occupant. For this purpose a torsion rod arranged within the drum may be used, for example, which is connected non-rotatably to the drum, on the one hand, and to the blocking disk on the other. In the case of restraint, when a torque as predetermined by the dimensioning of the torsion rod is exceeded, the drum can be rotated relative to the belt retractor with twisting of the torsion rod, belt webbing thereby being withdrawn from the drum and, due to the occurring plastic deformation of the torsion rod, energy is depleted to prevent any further increase in the forces acting in the seat belt.
A torsion rod having the deformation properties with good reproducibility as required for a force limiter is a complicated component.